TUMORS OF MIDDLE EAR &

CP ANGLEDr. Sithananda kumar. R

Objectives • To define boundaries of cerebellopontine

angle & jugular foramen

• To know the differential diagnosis for CP angle mass

• To know the approach to evaluate and manage a case of CP angle mass

• To know the evaluation and management of jugular foramen lesions

TUMORS OF CP ANGLE

Cerebellopontine Angle• Area of the lateral (quadrigeminal) cistern

containing CSF, arachnoid tissue, cranial nerves and their associated vessels.

• BordersAnterior –petrous part of temporal bonePosterior – cerebellumSuperior-pons cerebellar pedunclesInferior – cerebellar tonsils

INTERNAL ACOUSTIC MEATUS

ACOUSTIC NEUROMA

MENINGIOMA

EPIDERMOID (CHOLESTEATOMA)

ARACHNOID CYST

SCHWANNOMA OF OTHER CRANIAL NERVES (E.G. CN V > VII > IX, X,XI)

GLOMUS TUMOUR

METASTASIS

ACOUSTIC NEUROMAMisnomer

other names- vestibular schwanoma, Neurilemmoma Doesn’t arise from acoustic nerve

Not a neuroma

Arise from Schwann cells-schwanoma

Arises from vestibular nerve

Vestibular schwanoma6 % of all Intracranial tumors tumors

80 -90% of CPA tumors

95% Sporadic (unilateral)

5% -assoc with Neurofibromatosis type 2 (B/L)

No known race, gender predilection

age group of 40-60 years.

VESTIBULAR SCHWANOMA

Sporadic Type95% of all vestibular schwannomas

Unilateral

not associated with NF

seen in 5th -6th decade

Familial Type5% of all vestibular schwannomas

bilateral

Associated with NF-II

Seen in younger age groups

Genetics NF 2 Gene found at 22q12

Tumor suppressor gene preventing Schwann cell proliferation

Sporadic Variety (95%) Hypothesized that there are two hits to the normal NF

gene Neurofibromatosis type II

Autosomal DominantInherit one abnormal and one normal gene with one hit

to the normal allele. Blood tests available to screen family members.

PATHOLOGYBenign, encapsulated, extremely slow-growing tumour of the 8th nerve

Arises from Schwann cells

Equal incidence from superior and inferior vestibular nerve.

Arises within in the IAC in the region of scarpa’s ganglion which has the highest density of Schwann cells.

PATHOLOGY

Smooth surface , bright yellow to grey colour

Unencapsulated

Large tumors have cystic component

Microscopy /Immunohistochemistry• Antoni A- densely packed cells with small spindle

shaped nucleus

• Antoni B- loosely arranged vacuolated pleomorphic cells

• Verocay body- whorled or palisading appearance Antoni A cells

• Positive for vimentin, S-100 and neuron specific enolase

ClassificationDepending on the size, the tumour is

classified as:

• canalicular (when it is confined to IAC)

• Small size (up to 1.5 cm)

• Medium size (1.5 to 4 cm)

• Large size (over 4 cm)

Phases of Tumor Growth Intracanalicular:hearing loss, tinnitus, vertigo Cisternal:Worsened hearing and disequilibriumCompressive:Occasional occipital headacheCN V:Midface and corneal hypaesthesiaHydrocephalic:Fourth ventricle compressed and obstructed Headache, visual changes, altered mental

status

Cochleo vestibular symptomsEarliest symptoms -Tumour is still Intracanalicular Caused by pressure on cochlear or vestibular nerve fibres or on the internal auditory artery. Progressive unilateral sensorineural hearing and loss tinnitus Marked difficulty in understanding speech, out of proportion to the pure tone hearing loss(characteristic)

Sudden u/l sensorineural hearing loss-rare.

Vestibular symptoms Unsteadiness. True vertigo - seldom seen

Cranial nerve involvement

Vth nerve -earliest nerve to be involved.

Reduced corneal sensitivity, numbness or paraesthesia of face.

Indicates that the tumour is roughly 2.5 cm in diameter and occupies the cerebellopontine angle.

• VIIth nerve.-Sensory fibres are affected early.

• hypaesthesia of posterior meatal wall (Hitselberger's sign)

• loss of taste (as tested by Electrogustometry)

• Reduced lacrimation on Schirmer's test.

• Delayed blink reflex may be an early manifestation(Motor fibres - affected late)

• IXth and Xth nerves- dysphagia and hoarseness due to palatal, pharyngeal and laryngeal paralysis.

• Other cranial nerves. XIth and XIIth, IIIrd, IVth and VIth are affected when tumour is very large

Brainstem involvement Ataxia, weakness

numbness of the arms and legs with exaggerated tendon reflexes

Cerebellar involvement - seen in large tumours

Finger-nose test / knee-heel test

Dysdiadochokinesia

Ataxic gait

Raised intracranial tension - late feature

Headache, nausea, vomiting

Diplopia due to VIth nerve involvement papilloedema with blurring of vision

Audiological evaluation• PTA-SNHL (marked in high frequencies)

• Speech audiometry - poor speech discrimination

• Roll-over phenomenon

• Recruitment phenomenon is absent.

• Short Increment Sensitivity Index (SISI) test will show a score of 0-20% in 70-90% of cases.

• Threshold tone decay test shows Retrocochlear type of lesion.

Caloric test - diminished or absent response in 96% of patients.

Neurological tests -Complete examination of cranial nerves, cerebellar functions, brainstem signs of pyramidal and sensory tracts should be done.

Fundus –look for blurring of disc margins or papilledema

MRI with gadolinium contrast - Gold standard for diagnosis of acoustic neuroma.

Evoked response audiometry (BERA) - useful in the diagnosis of Retrocochlear lesions.

In the presence of VIII th nerve tumour, a delay of >0.2 msec in wave V between two ears is significant

Surgery -treatment of choice

Surgical approach will depend upon the size of tumour.

Various approaches are:Middle cranial fossa approach. Trans labyrinthine approach. Sub occipital (retro sigmoid) approach. Combined trans labyrinthine- sub occipital approach.

X-knife or Gamma knife surgery.Form of stereo-tactic radiotherapy

Radiation energy is converged on the tumour, thus minimising its effect on the surrounding normal tissue.

X-knife surgery is done through linear accelerator and gamma knife through a Cobalt-60 source

Causes arrest of tumour growth & reduction in its size.

In patients who refuse surgery Have contraindications to surgery In those with a residual tumor

Stereotactic surgery

Tumors of middle ear and mastoidPrimary Tumours Benign: Glomus tumourMalignant: Carcinoma, sarcoma

Secondary Tumours From adjacent areas, e.g. nasopharynx, EAC , parotid.Metastatic, e.g. from carcinoma of bronchus, breast, kidney, thyroid, prostate and gastrointestinal tract.

GLOMUS TUMORS

GLOMUS TUMOR• Most common middle ear neoplasm• Benign neoplasms of glomus bodies

–Glomus Tympanicum – Arnolds & Jacobson’s nerves–Glomus Jugulare – adventitia of jugular

bulb–Glomus vagale–Carotid body tumour

Pathology• Slow growing very vascular tumours

• 1% malignant

• 1 % secrete catecholamines

• Local bone destruction

• Can be very large at diagnosis

Often seen in the middle age (40-50 years).

Females are affected five times more.

Benign, non-encapsulated but extremely vascular neoplasm.

Rate of growth is very slow

Tumour is locally invasive.

• Microscopically-masses or sheets of epithelial cells which have large nuclei and a granular cytoplasm

• There is abundance of thin-walled blood sinusoids with no contractile muscle coat, accounting for profuse bleeding from the tumors.

Glomus Jugulare -arise from the dome of jugular bulb. Invade the hypotympanum and jugular foramen, causing neurological signs of IX th to XII th cranial nerve involt.

They may compress jugular vein or invade its lumen.

Glomus Tympanicum

They arise from the promontory of the middle ear and cause aural symptoms, sometimes with facial paralysis.

Spread of Glomus Tumour Initially fill the middle ear and later perforate through the tympanic membrane -present as a vascular polyp.

may invade labyrinth, petrous pyramid and the mastoid.

may invade jugular foramen and the base of skull, causing sixth to XII th cranial nerve palsies.

by spread through eustachian tube, it may present in the nasopharynx.

may spread intra cranially to the posterior and middle cranial fossae.

metastatic spread to lungs and bones is rare, but seen in 4% of cases.

metastatic lymph node enlargement.

Clinical featuresWhen tumour is intra tympanic hearing loss and tinnitus-earliest clinical feature

Hearing loss is conductive and slowly progressive.

Tinnitus -pulsatile and of swishing in character, synchronous with pulse can be temporarily stopped by carotid pressure

Otoscopy A red reflex through intact tympanic

membrane.

"Rising sun" appearance is seen when tumour arises from the floor of middle ear

Tympanic membrane appears bluish and may be bulging.

"Pulsation sign" (Brown's sign) is positive

Signs• Red/Purple mass behind tympanic membrane

• Hearing loss

• Brown’s sign

• Aquino’s sign

• Cranial nerve palsies

When tumour presents as a polyp profuse bleeding from the ear either spontaneously or on attempts to clean it.

Dizziness or vertigo

Facial paralysis may appear.

Examination reveals a red, vascular polyp filling the meatus

It bleeds readily and profusely on manipulation or at biopsy.

Cranial nerve palsies late feature

IX th to XII th cranial nerves may be paralysed.

dysphagia & hoarseness

unilateral paralysis of the soft palate, pharynx and vocal cord

weakness of trapezius and sternomastoid muscles.

Signs of intracranial involvement may also occur.

Auscultation with stethoscope over the mastoid may reveal systolic bruit

Some glomus tumours secrete catecholamines

Headache, sweating, palpitation, hypertension and anxiety

Rule of 10s

• 10% of the tumours are familial

• 10% multi centric

• 10% functional, i.e. they secrete catecholamines

Investigations• CT

• MRI

• Urinary/Serum catecholamines– Metanephrine, VMA

• MIBG scan

• Audiology

Treatment

1. Surgical removal.

2. Radiation.

3. Embolization.

4. Combination of the above techniques.